well, lucky you I can make this very easy for you! Notice the name Keyhole Sassy Doc? I can tell you who bred the horse (via pm) if you like. They might have the papers or info on who does. I am assuming this is a QH and you bought it in Az or it originated in Az and it has a brand on it as well? If not the brand then odds are I still know the breeders. They have only had 4-5ish stallions over the years (I can only remember 4) so it might be a lil hard but not impossible

haha so even easier for me, The sire of your horse is Boston's Watch me Too (might be slightly off on the spelling). He is a big buckskin stallion who is now in California I believe but seeing the age of your gelding it was while he was sitll here in Az